This longitudinal community study of young adults builds on a comprehensive data base of behavioral, social, health, familial, and academic measures collected at five timepoints from early childhood (age 5) to late adolescence (age 18). Continued study of this community sample at age 21 or 22 is important because young adulthood is a critical, but little studied, transitional period for the establishment of occupational choices, educational status, and social relations. This young adult period is complicated by a heightened risk for psychiatric disorders which may interfere with the successful acquisition of these adult roles. This study offers the rare opportunity to trace the onset, course, and consequences of disorders in a representative community sample by examining data collected over a 17-year span. Emphasis will be placed on the identification of those early psychosocial risks for disorders that can offer specific implications for targeted intervention and prevention efforts. Specific aims of the study are to: (1) determine the frequency and age of onset of selected DSM-III-R psychiatric disorders in young adults and identify early risks associated with onset; (2) examine the comorbidity (co-occurrence) of disorders in young adults, as well as the risks for and consequences of comorbidity; (3) identify psychosocial factors associated with the remission and continuity of disorders, suicidal ideation, and behavior problems; and (4) assess the impact of psychiatric disorders on young adult functioning. Beginning in the fall of 1993, approximately 350 of the 386 young adults (90%) last interviewed at age 18 will be re-interviewed by trained interviewers who have clinical experience. The 2-hour structured interview will include the DIS-III-R to assess psychiatric disorders, as well as questions about life events, vocational and educational status and goals, health, and interpersonal relationships. Young adults will also complete a battery of standardized instruments designed to measure self-esteem, perceived mastery, family cohesion, behavior problems, and social support. In addition, the mothers of these young adults will be interviewed about family history of disorders using the FH-RDC. Hypothesized relationships between risk factors and disorders, drawn from the literature as well as prior analyses of this study group, will be examined through univariate and multivariate techniques including logistic regression, survival analysis, and longitudinal random effects models. Findings will make several substantive contributions about the frequency, onset, comorbidity and impact of psychiatric disorders in young adults. In addition, the study's emphasis on the identification of early psychosocial risks for disorders will contribute to effective planning for programs aimed at prevention and early intervention.